Author(s)

Chari V. Kandala¹, Ron Holser², Jaya Sundaram³, Naveen Puppala⁴

¹National Peanut Research Laboratory, USDA, Dawson, GA, USA.
²Russell Research Center, USDA, Athens, GA, USA.
³Faculty of Engineering, University of Georgia, Athens, GA, USA.
⁴Clovis Center, New Mexico State University, Clovis, NM, USA.

An electronic method to estimate the moisture content (MC) of dry fruits by measuring the impedance (Z) and phase angle (θ) of a cylindrical parallel-plate capacitor with dry fruit sample between the plates, using a CI meter (Chari’s Impedance meter) at 1 and 9 MHz is described. Capacitance C was derived from Z and θ, and using the C, θ, and Z values of a set of dried cherries, whose MC values were later determined by the vacuum hot air-oven method, a calibration equation was developed. Using this equation, and their measured C, θ, and Z values, the MC of a group of cherries, not used in the calibration, was predicted. The predicted values were compared with their air-oven values. Similar predictions were done using the same method on dried blueberries. The method worked well with a good R² value, and showed a low standard error of prediction (SEP) in the measured MC range between 5% and 30% for cherries, and 9% and 22% for blueberries.

Cherries, Blueberries, CI Meter, Moisture Content, Capacitance, Impedance, Dry Fruits

Kandala, C. , Holser, R. , Sundaram, J. and Puppala, N. (2015) Nondestructive Determination of Moisture Content in Dry Fruits by Impedance and Phase Angle Measurements. Journal of Sensor Technology, 5, 73-80. doi: 10.4236/jst.2015.54008.